MiR-29a and Messenger RNA Expression of Bone Turnover Markers in Canonical Wnt Pathway in Patients with Ankylosing Spondylitis

Background: Recent studies showed that the canonical Wnt pathway and miR-29a play important roles in the pathogenesis of bone formation. We studied the levels of miR-29a and messenger RNA (mRNA) of bone turnover markers in the canonical Wnt pathway in ankylosing spondylitis (AS). Methods: The levels of miR-29a and mRNA of bone turnover markers in canonical Wnt pathway from peripheral blood mononuclear cells were determined by real-time quantitative polymerase chain reaction in 38 patients with AS and 32 healthy controls. Correlation analysis was conducted between the levels of miR-29a and mRNA and clinical measurements using Spearman's correlation test. Results: Compared to healthy controls, the levels of miR-29a, Dickkopf (DKK)-1, P-catenin and Runx2 mRNA were significantly higher in AS patients (p < 0.05). In contrast, the levels of Gsk-3 beta mRNA was significantly lower in AS patients than that in healthy controls (p < 0.05). Gsk-3 beta mRNA was positively correlated with beta-catenin mRNA expression (p < 0.05) and no other correlation was observed between any other markers (p > 0.05). Only DKK-1 mRNA expression was negatively correlated with disease course (p < 0.05) and no other correlation was observed between markers and clinical measurements (p > 0.05). Conclusions: The osteoblastic marker miR-29a and downstream mRNA of canonical Wnt signaling was upregulated in AS, suggesting their possible role in new bone formation in AS.